There have been scientific studies that have concluded that the ever-popular 5-second rule is a myth. These studies say that bacteria on floors dragged in on the bottom of shoes or dripped there from raw meet jump onto food the moment it touches the floor. The bacteria do not count to five before making their move.

A recent scientific study done by biology students and Anthony Hilton, Professor of Microbiology at Aston University in Birmingham, England found that “food picked up just a few seconds after being dropped is less likely to contain bacteria than if it is left for longer periods of time.”

Testing the 5-second rule on a variety of flooring surfaces - carpet, laminate and tiled surfaces - the researchers dropped toast, pasta, biscuit and a sticky sweet onto the floors for periods of time between 3 and 30 seconds.

Here’s what the students found.

  • Time is a significant factor in the transfer of bacteria from a floor surface to a piece of food.
  • The type of flooring the food has been dropped on has an effect, with bacteria least likely to transfer from carpeted surfaces and most likely to transfer from laminate or tiled surfaces to moist foods making contact for more than 5 seconds. 
They concluded that there was still a risk of contamination, but the shorter the food was on the floor, the less contaminated it was likely to be.

Another interesting finding in the study was that when they surveyed people, 87 percent of them said they would eat food dropped on the floor. So parents, if you’re in that 87 percent, you can sort of breathe a sigh of relief when you let our kids eat something that fell on the floor - if it’s picked up really fast. Your chances of them getting ill are less likely than if you let it stay there over five seconds.

I’ll admit. I’ve been known to follow the 5-second rule. I’m also known to follow my common sense so not everything that gets dropped on the floor is allowed to be consumed.

Do these scientific studies on the 5-second rule at all alter your use of the rule?

Also on MNN

The opinions expressed by MNN Bloggers and those providing comments are theirs alone, and do not reflect the opinions of While we have reviewed their content to make sure it complies with our Terms and Conditions, MNN is not responsible for the accuracy of any of their information.